I have been looking for a better version of this test too. Too bad the forum charter precludes posting links to likely replacements. Feel free to 'sticky' me with good ones!
IMHO the 'W3C mobileOK Checker' seems like it was written in 2009 by someone who has a 10mb data plan! I used it to 'mobilize' one site in 2011 and it ended up looking way too close to a starting page from a template vendor! The W3C has become a slow moving behemoth, look how long CSS 2.x final took! I wouldn't hope for a 2013 compatible version prior to 2016!